What is the workup for hypercalcemia and acute kidney injury (AKI) in an elderly patient?

From the Guidelines

The workup for an elderly patient with hypercalcemia of 12.4 mg/dL and acute kidney injury (AKI) should begin with immediate treatment while investigating the underlying cause, prioritizing aggressive IV fluid resuscitation and potentially adding furosemide or bisphosphonates as needed, as supported by recent guidelines 1, 2.

Initial Treatment and Diagnostic Approach

The initial approach should include aggressive IV fluid resuscitation using normal saline at 200-300 mL/hour to promote calcium excretion and improve renal perfusion. If the patient is volume overloaded or has severe AKI, consider adding furosemide 20-40 mg IV after adequate hydration. For moderate to severe hypercalcemia, administer zoledronic acid 4 mg IV or pamidronate 60-90 mg IV over 2-4 hours.

Diagnostic Workup

The diagnostic workup should include:

• Serum PTH, PTHrP, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D
• Serum and urine protein electrophoresis
• Complete blood count
• Comprehensive metabolic panel
• TSH Order a chest X-ray and consider CT scans of the chest, abdomen, and pelvis to evaluate for malignancy.

Common Causes and Considerations

The most common causes of hypercalcemia in elderly patients include primary hyperparathyroidism, malignancy (particularly multiple myeloma, breast, lung, and renal cell cancers), medications (thiazide diuretics, lithium, calcium supplements), and excessive vitamin D. The hypercalcemia is likely contributing to the AKI through vasoconstriction of renal vessels, decreased glomerular filtration rate, and nephrogenic diabetes insipidus causing volume depletion. Monitor calcium levels, renal function, and electrolytes closely during treatment, as rapid correction can lead to hypocalcemia and other electrolyte disturbances, as noted in guidelines for managing renal failure and hypercalcemia 3, 2.

Medication Considerations

When considering medications, especially in the elderly, it's crucial to be aware of potential adverse effects and interactions, such as those associated with diuretics, which can exacerbate renal impairment or lead to electrolyte imbalances 4, 5.

Conclusion is not allowed, so the response ends here.

From the Research

Workup for Hypercalcemia

• Hypercalcemia is defined as total calcium of greater than 10.5 mg/dL (>2.6 mmol/L) or ionized calcium of greater than 5.6 mg/dL (>1.4 mmol/L) 6
• The most important initial test to evaluate hypercalcemia is serum intact parathyroid hormone (PTH), which distinguishes PTH-dependent from PTH-independent causes 6
• An elevated or normal PTH concentration is consistent with primary hyperparathyroidism (PHPT), while a suppressed PTH level indicates another cause 6

Causes of Hypercalcemia

• Primary hyperparathyroidism and malignancy are responsible for greater than 90% of all cases of hypercalcemia 7
• Other causes of hypercalcemia include granulomatous disease, endocrinopathies, immobilization, genetic disorders, and medications such as thiazide diuretics and supplements such as calcium, vitamin D, or vitamin A 6

Hypercalcemia in the Elderly

• The prevalence of hypercalcemia in elderly women may be as high as 3% 8
• Important causes of hypercalcemia in the elderly include hyperthyroidism, malignant disease, and abrupt immobilization with previously elevated skeletal remodelling activity 8
• Thiazide diuretics may precipitate the hypercalcemic state 8

Acute Kidney Injury (AKI) and Hypercalcemia

• Hypercalcemia can result from excessive bone resorption, renal calcium retention, excessive intestinal calcium absorption, or a combination of these conditions 9
• The association of AKI and hypercalcemia is often related to comorbidity, such as cancer, multiple myeloma, hyperparathyroidism, sarcoidosis, vitamin D intoxication, and leprosy 9
• Treatment of hypercalcemia should be started with hydration, and loop diuretics may be required in individuals with renal insufficiency or heart failure to prevent fluid overload 7

Treatment of Hypercalcemia with AKI

• Intravenous bisphosphonates, such as zoledronic acid or pamidronate, are effective in treating hypercalcemia, but may be associated with increased rates of serum creatinine elevations in patients with preexisting renal dysfunction 10
• Glucocorticoids may be used as primary treatment when hypercalcemia is due to excessive intestinal calcium absorption (vitamin D intoxication, granulomatous disorders, some lymphomas) 6
• Dialysis may be indicated in patients with severe hypercalcemia complicated with kidney failure 7